The present invention relates to a headrest and a vehicle seat provided with the headrest. More particularly, it relates to a headrest capable of being in a head support state in which the headrest is raised with respect to a backrest seat and being tilted from the head support state to a storage state, and a vehicle seat provided with the headrest.
Generally, on the upper part of a backrest seat of a vehicle seat, a headrest for protecting the passenger's head is mounted. Conventionally, there has been publicly known a technique in which the lower parts of a pillar of the headrest are attached to a transverse rod extending in the right-and-left direction in the backrest seat so as to be rotatable in the front-and-rear direction, the pillar is attached so as to be movable in the right-and-left direction, and the headrest is tilted to the rear and stored after being moved transversely (see Japanese Unexamined Utility Model Application Publication No. 7-11951 (“the '951 Publication”)).
Also, there has been proposed a technique in which a headrest includes a pillar having a transverse shaft part and mounted on the upper part of a seat back; a headrest main body the lower part side of which is rotatably provided in the transverse shaft part of the pillar; and a tilting mechanism incorporated in the headrest main body to tilt the headrest main body backward, and the tilting mechanism includes a headrest urging element(s) for urging the upper part of the headrest main body to the rear side; a lock plate provided on the transverse shaft part of the pillar and having a first locking part; a latch provided on the headrest main body and having a second locking part capable of being locked to the first locking part of the lock plate; a latch urging element(s) for urging the latch so as to lock the second locking part to the first locking part of the lock plate when the headrest main body is in a raised state in which the headrest main body is approximately vertical; and an actuator for unlocking the second locking part of the latch from the first locking part of the lock plate against the urging force of the latch urging element(s) (Japanese Unexamined Patent Application Publication No. 2005-349915 (“the '915 Publication”)).
Furthermore, there has been proposed a technique in which in a tiltable headrest in which a bracket can be moved between a folded position and an upright position, a concave part is formed in a lock reciprocating member and a lock member respectively, and the lock reciprocating member can be made slidable between a lock position and an unlock position by a spring (International Patent Publication WO2005/120894A1 (“the '894 Publication)).
The publicly known technique described in the '951 Publication has a problem in that because the rotation supporting point of the headrest is present in the upper part of the backrest seat under the headrest, the headrest rotates backward greatly together with the pillar and therefore the displacement thereof is large, so that the space occupied at the storage time is large.
That is to say, when the headrest is tilted to the rear, one headrest fully projects to the rear side of the backrest seat. Also, this technique has a problem in that a pillar movement grooves must be formed in the upper part of the backrest seat, so that the construction is complicated, and also the backrest seat cannot be used in common with another backrest seat.
The publicly known technique described in the '915 Publication has a problem in that although the entire of the tilting mechanism of the headrest can be accommodated in the headrest main body, and the headrest has excellent versatility, since the first locking part of the lock plate and the second locking part provided on the latch to be locked to the first locking part are used, the lock plate and the latch are arranged in the tiltable direction of the headrest, so that some degree of size must be secured in the front-and-rear direction, and therefore there is a limit to the thinning of the headrest.
In the publicly known technique described in the '894 Publication, the concave part is formed in the lock reciprocating member and the lock member respectively, and the lock reciprocating member can be made slidable between a lock position and an unlock position by the spring. However, since the lock position and the unlock position are switched over by two members of the lock reciprocating member and the lock member, a spring force urging the bracket toward the folding direction is directly applied to the lock reciprocating member and the lock member. Therefore, the reciprocating motion of the lock reciprocating member is sometimes difficult to perform smoothly. Also, in the case where a plurality of lock members are present, the lock reciprocating member and all of the lock members are made slidable between the lock position and the unlock position by one lock reciprocating member, so that the size of the lock reciprocating member increases, so that this headrest has a disadvantage that a greater load is applied to the lock reciprocating member.